Protective apparatus and circuits



June 24, 1930. A. o. AUSTIN 1,766,738

PROTECTIVE APPARATUS AND CIRCUITS Filed June 25, 1924 2 Sheets-Sheet 11N VENTOR A TTORNE y 6 PROTECTIVE APPARATUS AND CIRCUITS Filed June 25,1924 V 2 Sheets-Sheet 2 $11" EF a 18 km E 19 g? i- .L

' INVENTORY ATTORNEYS Patented June 24, 1930 -omrsn stares; Parsererrlce ARTHUR o; AUSTIN, on BARBERTON, onro, ASSIG-NOR, BY MESNEASSIGNMENTS, To...

THE OHIO'BRASS COMPANY, or MANSFIELD, 01-110, A 'conronnrron on NEWJERSEY ..PROTECTIVE APPARATUS AND CIRCUITS Application filed. June 25,

' This invention relates to apparatus and circuits for protectionagainst lightning and other highfrequency and high potentialdisturbances in which a condenser forms a part of the apparatus. Theinvention has for its object the provision of protection both for thestation apparatus and the condenser.

, The invention is exemplified in the combination and arrangement ofparts shown in the accompanying drawings and described in the followingspecification and it is more particularly pointed out in the appendingclaims.

In the drawings Fig. 1 is a somewhat diagrammatical view showingacondenser housing in elevation as connected with a power line circuitand embodying one form of the present invention. v t

Fig. 2 is a circuit diagram showing one arrangement for the presentinvention.

The flow of current into a condenser varies approximately as thefrequency and the applied voltage. fThe severe electrical disturbanceswhich cause damage to apparatus'connected with transmission lines areusually at high frequencies. Lightning which is usually most severe asregards magnitude of voltage, isatvery high frequency or at leastproduces surge with steep wave front.

Since the currentfiow'ing into an electrostatic condenser variesapproximately directly as its electrostatic capacity and directly asjthevoltage, a high impressed voltage and a high frequenc'ylwillpermit avery considerable current to flow in the condenser.

If 'a condenser of sufiicient capacity is attached to a transmissionline in the vicinity in which protection is desired, a large part of-thehigh,frequencydisturbance may fiow into the condenser withoutraising thevoltage lto dangerous value. Where the amount ofenergy in the surge islarge, it is possible that the voltage of the condenser may beraised tosuch a value that it will form butllittle protection, or the condensermay atleast have to be considerably larger in order to'keep' down themaximum voltage, but with a properly designed condenser ade- 1924.Serial No. 722,206.

quate protection maybe provided in most cases.

In Fig. .1 there is shown a methodlof installing a condenser which hasprotection for the condenser itself and which provides protection to theapparatus in'the vicinity of the condenser. lVith this arrangementlightning protection is gained for the equipment in the vicinity of thecondenser, and, at the same time the condenser may be used for otherpurposes such as electrostatic coupling where the transmission line isused for a telephone circuit or for signalling purposes, forcommunication or for remote control of stations. In this figure thenumeral '1 designates a casing containinga condenser of proper'dcsign towithstand the voltage to which it will be subjected. The numeral 2designates a transmission li'ne 3 a resistance between the transmissionline and the disconnecting switch leading to the condenser and 4 aresistance connecting to the transformers of the station or otherelectrical equipment designated generally by 5. Only one line of thetransmission circuit is shown in Fig. 1 but it will be understood thateach conductor of the circuit will be provided with equipment similar tothat shown in the figure. A lead 6, running from the main conductorcircuit to the condenser disconnecting switch, serves to couple thecondenser to the line. The disconnectr 111 switch has a horn or contactarm 7 which is attached to the switch insulators 8.

This horn may be rotated by moving the handle 9, which rotates thedisconnecting switch insulators. \V hen the disconnecting switches arebeing closed, the horn? comes into contact with an arm 10. This isconnected to one end of a relatively high resistance 11. The other endof the resistance is connected to a fuse 12. The other end of the fuse12 is connected to the terminal of the bushing 13 leading to one elementof the condenser in the housing 1. The fuse 12 serves to disconnect theline in case of a short or ground in the condenser. Aninsulator 14supports the high resistance 11 and insulates the resistance from theconloo 15 insulates the fuse 12 from the condenser bushing terminal.This is desirable to cause the current to take the pro or path.

In closing the switch, contact 1s rst made 5 between the contacts 7 and10. If the switch is connected to a line carrying a high voltag trc willbe established between the hornstr contactmembers 7 and IO'before theycome into contact with each other. tends-tenet up all-oscillation whichan electrical disturban e which it is desirable to eliminate. By causingcurrent to flow through the relatively high re sistance 11, themagnitude of the disturbance can be greatly reduced or in some casesractically eliminated. As the switch arm continues to rotate, contact ismade with the horn 16, which is attached to one end of the protectingfuse 12. The hi h resistsince is then shunted and its efiect 7 inatedfrom the circuit.

In operation with the switch I, 10, 16 closed a hi 'h frequencdisturbance causes current to ow into e condenser in accordance with thelaws of the condenser. By the insertion ofa sufiiciently high resistance3, a very considerable dro in volt e fover the resistance?) will take pace, there y reducing the mag'nitudeof the surge.

Where the power apparatus has'some appreciable electrostatic capacity,a'further resistance 4 may be used. The drop in voltage will beproportionalto the resistance and to the current flow. Since the flow ofcurrent will be ver high with the hi h frequency, there will aconsiderable 0p in oltage over both the res1stance3and the resistancefd,even though the voltage'ma' not exceed ;that of" the normal line 'vtage.

as This plies only where high frequency is applied "During normaloperation, the current flowing over the resistances 3 and 4 willcauseloss in power, but since the current flowing on high voltage lines isusuall small compared to the current which wi w into the condenser under'ahigh frequency and a high voltage, a resistance may be used which willbe quite effective in absorting volt and ener at high freuenc'y, but wch will cause little loss at normalopera in; frequency and current ohthe system. I I Q'The system as own has very, material advant as smapparatus may be prowith a comparatively smallcondenser noes. "A,stationdrawing a relatem may usehigher resistances without proiicing asenous'loss.

Since the voltage drop due to high he quency will be in directproportion to the resistance an'dthe capacity of the condenser, it wouldseem that he same result may be I obtained by increasing the resistanceand 4 pro ly'pre itioningeither or both of a as.

lowering the capacity of the condenser, permitting a condenser of lowercapacity and less cost to be used.

The resistance in the circuit plays an important function in damp' outthe die turbance. There is a pos ifiility in some cases that theresulting e or'ogcfllation set up injthe system following lightning orany disturbance will cause more dama an ;ea itself-.1 fl wotenmnt monthswil'tand Y to absorb the ener of this disturbance and nger from thissource.

Where a coupli condenser is used, it is desirable to the apparatus sothat a practically the entire electrostatic capacity of the co' r-isusedfor gotection purposes. erder to do this, slow vol slde'of thecondenser is connected to the case 'or round -through a small gap 17."For the ghter surges a charging current due surge will pass lar 'ly'to1 the groundilead l fconn to the obndenser case. For severe .surges howher, Y Z the"a1 r,gap 1 7 breaks 'do'wn an con is much largercapacitance [to ground. The gap prevents a serious' intoltage to theapparatus connected to'thec denser and mits a comparatively amount ofnsulation on the low yoltiag'e side of 'the condenser aswell as makingthe entire caac1tance in the cond" available for ightni'ng' protection,A flow voltage side 0 the ondenser isptbvided with a 0011,? ductorlarsfor connecting it with carrier current amps us,

In operation e1 r I ance igor 4 may be eliminate' d,providgfiheimpedance of the line issuflicient to nee the necessary if'drog in voltage or .absorptionqf them h s fimqmwy fi z nx' weh ever, 'amnch larger-ccndenser wili be ec- 'essary if the'resi'st are not theusecf resistance, it is alsojpossible use a con h r and apmratns ofIOWQl-"afib d'ielectnc'strengthwhich y e'fiect a y rial saving Therugistances 31nd 4 may beinsth'e firm of concentrated? sistaaces'in theiorm of helices which have f a relatively-high resistance cbmparedwiththe conductor or in the. form'of an inductive f lead, providing thespacewill rmit. The resistance wire may bawoun inductivel parati l'.erate tfgresistance an oil ha to prevent flash-over. The oilbath ma alsobe used to cool the resistance.

For an incoming sur the resistance 3 is eflective' in reducing t evoltage on both the condenser and th other connected apm .und throughsistance. 4 is also valuable in protecting the station apparatus from abound charge released from the condenser.

' JTlie use of resistances 3 and-make it possible to provide protectionfor a single impulse of steep wave front, a resulting or sustainedoscillation, or the release of a bound surge; Either one or both of theresistances may be used to obtain the desired results. While theincoming lead or tap may be used for resistance 3 it is usuallyadvisable to use a concentrated resistance for 4, although asuitablelead may be used asin'8.

I claim i 1. The-combination with a transmission circuit .of-Lapparatusfor receiving power from saidgcircuit, a resistance interposed in serieswith said circuit and apparatus, a

condenser connected with said circuit in serieswith saidresistance butin shunt with said'powenreceiving apparatus and a fuse interposedbetween said condenser and circuit. V v a l I 2. The combination with atransmission circuit of. apparatus, for receiving power from saidcircuit, resistance interposed between; said apparatus and circuit, acondenser having one element thereof connected with said circuit-inseries with said resistance filllddll shunt with said apparatus, aconnect1onjw1thi the other element of said condenser to superiniposesignal impulses on said circuit and an arcing gap to ground from saidlast named element.

The'combination with a transmission circuit of power apparatus in serieswith said C11Cl1lt,- If6S1St2LI1QQ interposed in series withsaid powerapparatus and circuit, a condenser having one element thereof connectedinseries with aportion only of said resistance,fa signalling connectionwith the other eleinent of said condensenand a fuse interposed betweensaid condenser and reswitch is completely closed.

5. The combination with a transmission circuit of power apparatus inseries with said circuit,a resistance interposed in series with saidcircuit and power apparatus, a condenser connected with said circuit inseries with said resistance, an overload cut out interposed in se ieswith said condenser, a switch for making and breaking the connectionwith said circuit and a resistance connected in series with saidcondenser for a period of time during the closing of said switch but cutout of said circuit when said switch is completely closed.

6. The combination with a condenser housing of a bushing insulatortherefor, a fuse member supported by said bushing insulator at one endof said insulator and externally thereof and a switch element alsosupported by said bushing insulator.

7. The combination with a condenser housing of a switch supported bysaid housing and insulated therefrom, an insulator bushing for saidhousing, a fuse elementsupported on said housing and insulatedtherefrom, a resistance element on said housing and insulated therefromand means connected with said switch for short-circuiting saidresistance element when said switch is closed.

8. Thecombination with a transmission circuit of power apparatusconnected with said circuit, a resistance in series with said circuitand power apparatus, a condenser having an element thereof connectedwith said circuit in series with said resistance and in shunt with saidpower apparatus, the other element of said condenser being provided witha spark gap to ground.

9. The combination with a transmission circuit of power apparatusconnected with said circuit, a condenser having one element thereofconnected with said circuit, a case for said condenser and a groundconnection for said case, the other element of said condenser having aspark gap opening to said case.

10. The combination with a transmission circuit of power apparatus inseries with said circuit, resistance interposed in series between saidpower apparatus and circuit, a condenser having one element connected inseries with a portion only of said resistance, there being interposed afuse and disconnecting switch between said condenser and circuit, aresistance element,means op- 'erated by said switch for inteiposing saidresistance element in series with said condenser while said switch isbeing closed, means for connecting apparatus to the other element ofsaid condens r, said means being provided with a spark ga i to ground.

11. The combination with a transmission line, and apparatus forreceiving power from said line, of a condenser connected to said line ata point between said line and apparatus, resistance in series with saidcondenser and line, a signal circuit conductor connected with theopposite element of said condenser from that connected to said line,there being a spark gap to ground from said signal circuit, and agrounded capacitance member disposed adjacent said con denser.

, 12. The combination with a power transmission ,line and apparatus forreceiving power therefrom, of a branch circuit conrn-tins and line, a

fuse supports a one end of said a use being connected with f 6 mentthereof connected to said branch circuit, a signal circuit conductorconnected to the other elements of said condenser, and a casing for saidcondenser serving as an additional capacitance member in co-operaum tionwith the firstmamed elementof said condenser, said casing beinggrounded.

'13. In combination, a traimmission line, station apparatus connectedwithsaid line, a resistance interposed between said appa unded metalliccondenser housing! having condenser elements therein, a carrier currentconductor insulated from said housing and connected with one element ofsaid condenser, a spark gap between said housing and carrier currentcircuit, a bushing insulator extendi from said housing, a conductorconnects with theiother element-of said condenser and extending thro hsaid bushing insulator, a said bushing insulator,

said conductor, a switch le mounted on said bushing insulator anconnected with the other end of said fuse, a switch arm arrangedtoxconnect said switch pole to said transmission line at a point betweensaid line and station apparatus, a spring-held contact member mounted onsaid bushing insulatcr and arranged to engage said switch arm prior toengagement of said arm .with said switch pole when said switch'ai'm ismoved to closed position, and a residence element connected between said"spring-held contact memberand fuse, said resistance element being'shortcircuited whensaid switch arm engages said switch pole. 14. Incombination, a grounded metallic housing, condenser elements disposedwithin said housi ,a carrier current conductor connected with one ofsaid elements and in- 5 sulated from said housing, a spai'kgap betweensaid housing'and carrier current circuit, a bushing insulator projectingfrom said housing, a conductor connected with a) the other element ofsaid condenser and extending through said bushi insulator, a terminalmember for said con uctor carried by said bushing insulator, aninsulator mounted on saidtermina-l member, a tubular 5 housing carriedby said insulator, a fuse disposed within said housing and having oneend thereof connected with said terminal member, a switch pole mountedon said tubular housing and connected with the other end of said fuse, asecond insulator mounted on said tubular housing, a resistance elementcarried b{ said second insulator and having one end t ereof connectedwith said switch pole, a spring-held contact memg her cemiected'withtheother end ofsaid resistance element, a movable switch arm ern whenclosedto first spring-held contact memfir and thereafterg with.,saidswitch pole, said resistance-e F; ment be' short circuited when said sarinfl-e said switeii Ib, a' rotatii I 5 menu rupright'pcst, an i mlatorby saidpostfor supporting said switch k a transmission line, I saidtransmimion line, and'station apparatus 1 connected through said timewith i transmission line, said switch aim being connected with saidtransmission line between said line and station apparatus. 15.Theicombination with a transmissicm circuit, of apparatus for receivingpower from said circuit, a resistance interposed in series with saidcircuit and apparatus, a branch line having one end thereof ed with'aaidcircuit between said y and ap a condenmielectrically nected in saidbranch'line and a fuse interposed between said comb ner-and circuit; 16.The combination m a'transmissien circuit, of apparatus ferreceivingi-oin said circuit, a between apparatus and'cireuit, a branch linehavingone end thereof with said cimuit'betweiegi use and said apparatus,a con user if one element thereof connected with said ranch 'line,*i-rsignalling connection with-the other elel ment of said condenser tosuperimpose nal' impulses on said circuit and an arcing, gaepltto groundfrom m V l y] name to this specification onthis std a; otJune A. D.1924. Y ARTHUR o. AUSTIN.

